High-voltage isolator with contact turning about a vertical axis

ABSTRACT

A high-voltage isolator comprises a vertical support insulator carrying an obliquely upwardly directed isolator blade, which cooperates with a stationary countercontact suspended in a bus bar conductor. The isolator is operated by turning the support insulator at least 90* about its longitudinal axis.

United States Patent Inventor Appl. No.

Filed Patented Assignee Priority Georg Teodor Trolin Vasteras, Sweden Apr. 16, 1970 Dec. 21, 197 l Allmanna Svenslta Elektrisltl Aktiebollget Vasteras, Sweden Apr. 18, 1969 Sweden HIGH-VOLTAGE ISOLATOR WITH CONTACT TURNING ABOUT A VERTICAL AXIS 7 Claims, 5 Drawing Figs.

US. Cl

Int.Cl ..I-I0lh 31/00 [50] Field of Search 174/43, 45; 200/48, 48 RP, 48 VR [56] References Cited UNITED STATES PATENTS 3,526,732 9/1970 McKinnon 200/48 A Primary Examiner-Herman J. Hohauser Attorney-Jennings Bailey, Jr.

ABSTRACT: A high-voltage isolator comprises a vertical support insulator carrying an obliquely upwardly directed isolator blade, which cooperates with a stationary countercontact suspended in a bus bar conductor. The isolator is operated by turning the support insulator at least 90 about its longitudinal PATENTEU 05021 um 3.629531 SHEET 1 BF 2 Fz'g/ I GEORG TEODOR TROLIN PATENIEI] mm an SHEET 2 OF 2 w H H6 M i E i BHHHE INVENTOR. a EORG TEODOR TROLIN HIGH-VOLTAGE ISOLATOR WITH CONTACT TURNING ABOUT A VERTICAL AXIS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called single-column isolator, preferably intended for use in high-voltage switchgear of the outdoor type. The isolator is provided with a substantially vertically arranged support insulator carrying an obliquely upwardly directed elongated isolator blade, the upper end of which can be brought into contact with a stationary countercontact element.

2. The Prior Art When planning a high-voltage switchgear, it is often of considerable importance to reduce the space requirement as much as possible. If, as in the present case, the switchgear is to be outdoors, room must often be made for the installation by extensive blasting, excavation and levelling operations and from the economic point of view it is of course particularly desirable to be able to reduce the extent of such relatively expensive work. This can be achieved, among other things, by selecting space-saving isolators.

A conventional type of high-voltage isolator has the isolator blade divided into two halves of equal length which are attached each to one of two insulators positioned vertically and turned by about 90 around their longitudinal axes during opening and closing. Isolators of this type require rather much space in the horizontal plane. This space can be decreased considerably by using so-called pantograph isolators in which atonglike contact element is arranged to grip a countercontact element suspended in a conductor. Such an arrangement is particularly suitable for connection of two conductors situated at different levels, and it is often used in coastal areas, for instance, where it is necessary to clean salt deposits from the isolator-insulator while still maintaining voltage in the upper conductor. However, pantograph isolators are generally relatively complicated and expensive.

It has also previously been proposed to construct a highvoltage isolator having two vertical insulators arranged at different heights. One of the insulators, which is pivotable through 90 about its longitudinal axis, carries the isolator blade while the other insulator carries the stationary countercontact. The difference in height between the connection terminals arranged on the two insulators is, in this arrangement, at least equal to the phase distance required for the operating voltage in question. Furthermore, the horizontal distance between the longitudinal axes of the insulators must be at least as great as the distance required between any phase and earth, since the insulators with their contact elements form a structural unit held together by an iron stand, the earth potential being raised to the level of the connection terminal of the lowest insulator. This has the disadvantage, among others, that the compartment width of the switching station where this isolator is used will be unnecessarily large. Because of the relatively great radial distance between the turning axis of the isolator-insulator and the countercontact element, the isolator also requires relatively great operating power and the isolatorinsulator will be subjected to a relatively large torsional and bending moment.

SUMMARY OF THE INVENTION The above-mentioned disadvantages can be avoided with the isolator according to the present invention which is characterized in that the support insulator is arranged, when the isolator is operated, to be turned at least 90 about its longitudinal axis, and in which the free end of the isolator blade, when operated, describes a part of a circular path lying in a horizontalplane, the center of the circle lying on the longitudinal axis of the pivotable insulator and its diameter being substantially equal to or less than the length of the isolator blade. Such an isolator is considerably simpler and cheaper than a pantograph isolator and has the same advantages. It is thus relatively easy to operate and the mechanical strain on the isolator-insulator will be rather reasonable.

The countercontact element is suitably constructed with attachment members for suspension in a conductor or for attachment to a support member for the conductor. Since, in the same way as with a pantograph isolator, the countercontact element forms a structural part which is constructively separated from the rest of the isolator, a particularly simple isolator construction is achieved, the earthed apparatus stand of which need not be higher than the lower end of the pivotable isolator-insulator.

In order to reduce the space required for the switching station in the horizontal plane, while retaining the required distance between the isolator blade in its off position and the conductor system in which the countercontacts are suspended, it is advantageous if the attachment member for the countercontact consists of an elongated metal peg provided with connection terminals for the conductor.

In order to further reduce the space requirement of the isolator, the isolator blade may suitably be curved in such a way that its center of curvature is at the countercontact when the isolator blade is in its off position. Alternatively, the isolator blade may be straight and mounted on a metal arm projecting horizontally from the upper end of the isolator insulator.

Furthermore, the isolator blade may with advantage be attached to the pivotable insulator in such a way that when necessary it can easily be lowered to horizontal position. The contact means will thus be easily accessible for inspection and the isolator-insulator can be cleaned even while the voltage is maintained on the upper conductor.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be further described with reference to the accompanying drawings FIGS. 1 and 2 show in plan view and side view, respectively, an isolator constructed in accordance with the invention and mounted in a compartment of a high-voltage switching station.

FIG. 3 shows the same type of isolator used as bypass isolator for a line connected to the switching station.

FIGS. 4 and 5 show in two views perpendicular to each other how the isolator blade may be suitably attached to the appropriate pivotable insulator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The switching station compartment shown in FIGS. 1 and 2 contains a three-phase bus bar system 1, 2, 3 and a threephase branch line 4, 5, 6, connected to this by an isolator. The bus bar system and the branch line cross each other at different levels. Each isolator pole is constructed of a vertically oriented pivotable insulator 7 which carries an oblique isolator blade 8. The isolator blade 8 is shown both in its on position (unbroken lines) and its off position (broken lines). The isolator blade cooperates with a countercontact 9 on the bus bar system, this contact being in the form of a peg projecting downwardly from the bus bar system. An additional decrease in the width of the compartment of the switching station is possible if this peg is made even longer than shown. At the upper end of the insulators 7 the branch line 4, 5, 6 is connected to the isolator by means of connection terminals which are pivotable in relation to the insulators 7.

The isolator 7, 8 and the bus bar system 1, 2, 3 are attached to the same iron stand which is constructed as a frame having two parallel beams 10 and 11 arranged horizontally at different levels, and is positioned on two bases 12 and 13.

FIG. 3 shows in side view how a branch line 14 may be connected to a switching station. The line enters the switching station through a cable box 15, a voltage transformer 16, a current transformer 17, a line isolator 18 of conventional design and continues through a circuit breaker, not shown, and a bus bar isolator, also not shown, to the bus bar system of the switching station. Parallel to the circuit breaker and the isolators is a bypass connection isolator 19 of the type proposed according to the present invention. This isolator, as can be seen, is carried on a stand 21 arranged to carry the bypass connection conductor 20, so that no special base for the isolator 19 is required and the stand components necessary for this isolator are limited to a bracket 22. From FIG. 3 it is clear that the space necessary for the switching station in the horizontal plane is less than if an isolator of the same design as the line isolator 18 were used as bypass connection isolator.

H68. 4 and 5 show how the isolator blade 8 is attached to the pivotable insulator 7. The isolator blade 8 in this embodiment is pivotably suspended on a horizontal joumaling peg 23 and is normally held in position by a cotter pin 24. lfthe cotter pin 24 is removed, the isolator blade can be lowered. The contact means is then easily accessible for inspection and repair and there is more space for working in the switching station. In industrial areas with polluted air or in coastal districts where salt deposits easily occur on the insulator porcelain, the advantage is also gained that the isolator-insulators 7 can be cleaned while operation is continued on the bus bar system.

I claim:

1. High-voltage isolator comprising a frame (l0, 11) a substantially vertically arranged upwardly extending support insulator (7) carried by said frame, a stationary countercontact carried by said frame at a higher level than said support insulator, an obliquely upwardly directed elongated isolator blade, means mounting said isolator blade for turning movement about the vertical axis of said support insulator through an angle of at least 90 between positions engaging and spaced from said countercontact element in a circular path lying in a horizontal plane, the center of the circle lying substantially in the longitudinal axis of the support insulator and its diameter being not substantially greater than the length of the isolator blade a second support insulator carried by said frame and extending downwardly therefrom, the countercontact being mounted at the lower end of said second support insulator.

2. High-voltage isolator according to claim 1, in which the isolator blade is secured on the support insulator, and the mounting means comprises means mounting the support insulator for turning around its vertical axis.

3. High-voltage isolator according to claim 1, in which said second support insulator includes means adjacent its bottom end for holding a conductor.

4. High-voltage isolator as claimed in claim 1, having means at the upper end of the support insulator for holding a conductor.

5. High-voltage isolator as claimed in claim 1, including means mounting said isolator blade on the upper end of the support insulator for swinging with respect thereto about a substantially horizontal axis.

6. High-voltage isolator as claimed in claim 5, including means operatively connected with the support insulator and the isolator blade for holding the isolator blade in upright position.

' 7. High-voltage isolator as claimed in claim 1, in which in such spaced position the shortest distance between the countercontact and the isolator blade is substantially equal to the diameter of said circular path.

l l t t 

1. High-voltage isolator comprising a frame (10, 11) a substantially vertically arranged upwardly extending support insulator (7) carried by said frame, a stationary countercontact carried by said frame at a higher level than said support insulator, an obliquely upwardly directed elongated isolator blade, means mounting said isolator blade for turning movement about the vertical axis of said support insulator through an angle of at least 90* between positions engaging and spaced from said countercontact element in a circular path lying in a horizontal plane, the center of the circle lying substantially in the longitudinal axis of the support insulator and its diameter being not substantially greater than the length of the isolator blade, a second support insulator carried by said frame and extending downwardly therefrom, the countercontact being mounted at the lower end of said second support insulator.
 2. High-voltage isolator according to claim 1, in which the isolator blade is secured on the support insulator, and the mounting means comprises means mounting the support insulator for turning around its vertical axis.
 3. High-voltage isolator according to claim 1, in which said second support insulator includes means adjacent its bottom end for holding a conductor.
 4. High-voltage isolator as claimed in claim 1, having means at the upper end of the support insulator for holding a conductor.
 5. High-voltage isolator as claimed in claim 1, including means mounting said isolator blade on the upper end of the support insulator for swinging with respect thereto about a substantially horizontal axis.
 6. High-voltage isolator as claimed in claim 5, including means operatively connected with the support insulator and the isolator blade for holding the isolator blade in upright position.
 7. High-voltage isolator as claimed in claim 1, in which in such spaced position the shortest distance between the countercontact and the isolator blade is substantially equal to The diameter of said circular path. 